Former Prime Minister Junichiro Koizumi stuck his head into a political brouhaha Thursday to rap Prime Minister Taro Aso for his imprudent remarks on postal privatization, threatening to stir up even more anti-Aso sentiment.

"As for the prime minister's recent remarks, they make me laugh. I am just stunned rather than being angry," the Lower House lawmaker told members of a Liberal Democratic Party panel on postal privatization.

Koizumi, one of the most popular prime ministers ever, also gave Aso a veiled warning.

Although some of the LDP's younger members have been told to refrain from "shooting (Aso) in the back," Koizumi said, Aso now seems to be "shooting from the front at those who (face an election)."

"It's been a long time since I've seen Koizumi's angry face," Upper House member Ichita Yamamoto said, noting that since Aso will still be the LDP president when his party's ranks run in the next election, he's unsure how they will fare.

"There are more and more members who think they cannot (win that election) with the current administration," he said, adding the public has reacted harshly to Aso's comments.

Since Koizumi remains popular with the public and influential within the party, his rare intervention in the fracas might motivate those unhappy with Aso's leadership to take action.

It is rare when Koizumi takes the political stage nowadays. He has barely spoken to the media since stepping down as prime minister.